Drafting instrument



g- 9 95 H. E. WALKER 2,607,119

DRAFTING INSTRUMENT I I 2 SHEETS-SHEET 1 Filed NOV. 2, 1946 l5 HVVENTUR.

25 FUTORNE Y5 Aug. 19, 1952 H. E. WALKER 2,607,119

DRAFTING INSTRUMENT Filed Nov. 2, 1946 2 SHEETS-SHEET? INVEN TOR. L HE/way E. WflL/(ER HTTO/QNEYS.

sired points the spline may be curved by shifting the weights so as to form the desired curve and the weights will then holdthe spline in the desired curve or curves. Any number of weights may be used and the spline may be curved sinuously instead of a single curve.

Said spline may be of any length and any num-' ber of weights may be used.

Supported on said spline for movement longi tudinally of the latter is a carriage, generally designated 6. This carriage is removable from the spline, as will appear later on and'carries the marker that will make the desired lineon the surface on which the spline is positioned.

Carriage 6 comprises an elongated carriage member I that is adapted tofextend'over the upper edge 8 of the spline longitudinally of the latter. This member 1 may be in the form of a hat, straight bar positioned with its flat sides horizontal, as shown in Figs. 1, 2; f

A ball bearing is carried at each end of said member 7, said bearings being'numbered 9, lb. The bearing 9 .pivotally supports one end of a vertical pivot H that extends upwardly from a head element l2, said element depending from the lower side of member .7. The head element I2 is rotatable relative to member I about the vertical axis of said pivot ll.

The element 12 is formed with a vertical,

downwardly opening slot I3' (Fig. 4) in its lower side and in which slot said spline is normally positioned. At the upper end of slot [3 is a roller I 4 that engages the upper edge of the spline (Fig. 7). Roller Hl extends transversely across said upper edge and supports the element l2 for movement along said spline. V

The portion I5 of element l2 that forms one side of slot [3 (Fig. 5) is hingedly secured to the main body of said element i2 by means of a link l6 that is pivoted at l1; l8 at its ends to said body and to portion If: so that the latter may move toward andaway from the opposite side of said slot. A leaf spring l9 secured to the main body of element I2 yieldably engages the portion 45 to urge it toward the opposite side of slot [3 at all times.

The said portion' l5 carries twopairs of vertically aligned and vertically spaced balls 22, 23 in the side thereof that defines one side of slot 13 and these balls project into said slot, while the portion 21 of element 12 that forms the other side of slot l3 carries one pair of balls 20. The pair of balls 22, 23 are equally spaced irom the pair of balls 20, and the upper balls of all pairs are in the same horizontal plane while the lower balls of all pairs are also in a common horizontal plane below the upper'balls'. The spline l is held between the balls at one side of slot l3' and the balls 22,23 at the opposite side. By this means the element 12 cannot wobble on the spline'(due to the upper and lower sets of balls) and the spline can bend in the slot without localized distortion. The movement permitted by the movable portion l5 will enable the ball 22, 23 to move toward and away from portion 21 as the degree of the curve varies.

Secured to the portion 2! of element I2, and rigid therewith is a vertical plate 25 (Figs. 1, 2). This plate extends along the member I, at a level 4 below it, and is provided with a horizontal pivot 26 adjacent the end remote from said element l2. Pivotally supported on this pivot 26 is an arm 2'! that extends forwardly alongside plate 25 back toward the element 12, but on the side of plate 25 that is opposite said element.

I g The arm 21 is relatively wide at it outer end portion that is adjacent element [2 and extends to the upper edge of plate 25 adjacent said element where. it carries a horizontal pivot 28 on which is supported a segment plate 29, at the radial point of the latter.

Extending radially of said pivot and secured to said segment plate is a tracing pin 30 that is adapted to slidably engage the surface on which the spline is supported when said segment is rotated on pivot 28 -'to bring said pin vertical and pointing downwardly.

Also extending radially of pivot 28 and secured to said seg'ment plate is a well-type; lettering'pen 31, such as is employed for use with the ordinary Leroy or Wrico lettering sets. When the segment ZS-is rotated'so that the pen SI is vertical and in substantial writing engagement with the surface 33 on'which spline l is' 'sup' ported, it will be seen that said pen will mark the curve as'the 'carriag'e'is moved along the spline.

A spring 34 adjacent pivot 2t that connects arm 27 with plate 25 functions to'yieldably'urge the pen 31' or tracing pin 33 against said surface 33.

A detent spring 35 carried 'on arm 21 engages a depression in the segment29 adjacent pen 3! or pin '38 according to which is vertical for releasably holding said segment in adjusted position.

The elongated carriage member 7 is provided at its end opposite the element I 2 with a foot element 40 that is below said member and that is pivotally connected to said member by a pivot 4| that is in ball bearing Hi. This foot element 40 (Fig. 7) is also formed with a downwardly opening slot 42 therein, in which the spline is receivedQanda roller orpin 43 in the upper end of said slot engages the upper edgeof the spline. The slot 42 is just a-plain slot in this instance and without balls such as were used in element [2; v

From the foregoing it will be seen that the carriage S'hasa two point contact with the upper edge of the spline l at roller M and pin 43 and theelernent 12 cannot tilt to cause the vertically aligned balls 21!, 22, or 23 to tilt out of their alignment perpendicular to spline I. In other words, the carriage will always remain level and will not tilt in any direction relative to the spline.

The central axis of pivot II that carries the element 12 extends through the spline l and the arrangement of balls 20, 22, 23 is such that the pen 3| 'or'pin '38, whichever is vertical and in working position, will be in a vertical plane that extends through the balls 20 and that bisects the space between the pairs of balls 22, 23, which plane is perpendicular to a plane extending through the pairs of balls 22, 23. Thus the marker, whether pen or pencil, or the pin 39, whichever is in working position, will be on a line that is perpendicular to the tangent of that portion of the curve of spline I that is between the pairs of balls 22, 23 and the marker or pen willinevitably follow a path that is parallelwith the spline.

In operation the draftsman' first preferably swings the segment plate 29 to bring the tracing pin into vertical operating position. He then adjusts the spline so that the pin will pass through the points plotted on the paper or surface 33. This is easily and quickly done by shifting the weights to move the spline to the desired curve. Then the segment is swung to bring the pen into operating position and the curve is quickly inked in by a single movement of the carriage along the spline. No blotting can possibly occur and the line is of exactly the same thickness from end to end.

In sheet metal shops, shipyards and other manufacturing plants, a burning torch 59 (Fig. 11) may be substituted for the pen, or any other desired implement may be so substituted. By this means the use of templates may be omitted as the spline provides means that enables the workman to follow any curve of practically any degree and kind.

In the claims, the use of the Word marker is intended to include a torch, pencil, pen, scratch awl, cutter, welding rod, etc.

It is to be noted, as seen in Fig. 10, that the plate will swing outwardly and away from the convex side of the curved spline when the carriage goes around a curve such as illustrated. In Fig. 2 it will be seen that the plate 25 is free to swing past the member 40 in the opposite direction or toward the spline when the marker is moved along the concave side of a curve made by the spline. Thus the device may be used for making a sinuous line as well as other curves, such as parabolas, hyperbolas or irregularly plotted curves.

It is to be understood that the detailed description and drawings are not to be considered restrictive to the invention, but merely illustrative of a preferred form.

I claim:

1. A drafting instrument comprising a spline adapted to be supported on edge on a plane, generally horizontally disposed surface and free for bending into any desired circular or non circular curve on said surface, a carriage element supported on the upper edge of said spline for movement longitudinally of the latter, a plurality of bearings on said carriage element including a horizontally spaced pair engaging one side of said spline at spaced points and one bearing engaging the opposite side of said spline at a point intermediate said pair, means for yieldably urging said bearings against said spline for holding the carriage on the spline free from play during movement of said carriage along said spline irrespective of the degree of curvature of said spline, and a marker on said carriage element spaced from one side of said spline, means securing said marker to said carriage element in a vertical plane extending through said one bearing and perpendicular to a plane bisecting the bearings of said pair, said marker being adapted to slidably engage said surface for marking on the latter, a head member pivotally secured at one end to said carriage element for movement of the former about a vertical aXis relative to the latter, and means at the opposite end of said head member pivotally secured thereto for movement about a vertical axis and supported on the upper edge of said spline for movement along the latter together with said carriage element.

2. A drafting instrument comprising a spline adapted to be supported on edge on a plane, horizontal surface and free for bending into any desired circular or non circular curve on said surface, a carriage element supported on the upper edge of said spline for movement longitudinally of the latter, a plurality of bearings on said carriage element including a horizontally spaced pair engaging one side of said spline at spaced points and one bearing engaging the opposite side of said spline intermediate said pair, each bearin of said pair comprising a pair of vertically spaced balls and said one bearing comprisin a pair of vertically spaced balls, means yieldably urging said pair of bearings against said splin and urging said spline against the balls of said one bearing, a marker on said element spaced from one side of said spline and in slidable engagement with said surface, and means securing said marker to said carriage element in a vertical plane extending through said one bearing and perpendicular to a plane bisecting the elements of said pair.

3. A drafting instrument comprising a spline adapted to be supported on edge on a plane, horizontal surface and free for bending into any desired circular or non circular curve on said surface, an elongated carriage member adapted to extend longitudinally over the upper edge of said spline, a head element at one end of said carriage member pivotally secured thereto for swinging about a vertical axis and depending from said member, a foot element at the opposite end of said carriage pivotally secured thereto for swinging about a vertical axis and depending from said member, said head element and said foot element each being formed with a downwardly opening slot in which said spline is slidably received, a bearing in the closed upper end-of each slot engaging the upper edge of said spline, a marker carried by said head element spaced from one side thereof and from said spline and adapted to engage said surface for marking on the latter, means securing said marker to said head element for swinging of the marker with said head element about the vertica1 axis of the pivot supporting the latter, and means for holding said marker at a point along a line perpendicular to the tangent of the curve of said spline at the point where said vertical axis of the pivot of said head member extends through said spline, said latter pivot being positioned to extend through said spline at all times during movement of said latter head along said spline.

HENRY E. WALKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 465,264 Hare Dec. 15, 1891 940,118 Bartels et al Nov. 16, 1909 1,042,066 Zsinko Oct. 22, 1912 1,141,640 Huguenin June 1, 1915 1,162,587 Eimann Nov. 30, 1915 1,646,129 Wagnes Oct. 18, 1927 1,996,876 McDowell Apr. 9, 1935 2,045,360 Kaufmann June 23, 1936 2,383,208 Mustered Aug. 21, 1945 2,412,598 Brush Dec. 17, 1946 FOREIGN PATENTS Number Country Date 2,496 Great Britain of 1894 230,571 Great Britain Mar. 19, 1925 510,878 Great Britain Aug. 8, 1939 803,794 France Oct. 8, 1936 

